The official government line on the cow thing is that they really frown on this activity. Supposedly, they have closed down all of the shooting ranges but they are still in open operation near to the airport (run by the army!!).
I seem to recall that the rocket launcher was $400 and they drive you to some more secluded spot. This was quite a relief, when I heard, as it didn't seem like the sort of activity to be taking place so close to the international airport.
The grenade throwing, at the site near the airport, involved throwing the grenade into a large pond, and so it lost some of its appeal.
Running up a large bill through using gun set to automatic hasn't been an issue when I've been there as they give you a magazine containing the number of rounds you want to purchase. A dozen rounds in an AK47 set to automatic was enough for me to realise that I wasn't cut out to be a soldier and that my ears and shoulder are made of schoolboy-like material.
The AK47 and M16 are things that I do not think I would get to try anywhere else in the world but even the revolver and shotgun are things that I could not achieve easily here in the UK. I'd suggest it as somewhere experience and it is just another of those things to act as an interlude from mongering. (Probably sacrilege suggesting that anyone might want a break from mongering but there you go!!)